DEBT (Narrative) (Details) - USD ($) $ / shares in Units, shares in Thousands				12 Months Ended
	Dec. 31, 2016	Dec. 15, 2016	Jul. 02, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 07, 2016	Aug. 28, 2015	Jul. 02, 2015	Jun. 15, 2011
Debt Instrument [Line Items]
Amortization of debt issuance costs				$ 2,529,000	$ 2,264,000	$ 2,571,000
Carrying amount of liability	$ 0			0	218,240,000
Principal amount paid				$ 184,313,000	$ 2,519,000	$ 0
Stock issued during period, shares, conversion of convertible securities (in shares)		2,900
Common stock from the exercise of call option with hedge participants (in shares)		2,900		2,946
Common stock from the exercise of call option with hedge participants, value				$ 123,100,000
Price per share (in dollars per share)	$ 41.78
Common Stock
Debt Instrument [Line Items]
Stock issued during period, shares, conversion of convertible securities (in shares)		2,900		2,946
Settlement of convertible notes		$ 122,000,000		$ 29,000
Treasury Stock
Debt Instrument [Line Items]
Common stock from the exercise of call option with hedge participants (in shares)				2,946
Common stock from the exercise of call option with hedge participants, value				$ 123,051,000
Treasury Stock | Weighted Average
Debt Instrument [Line Items]
Price per share (in dollars per share)	$ 41.78
Term Loan
Debt Instrument [Line Items]
Weighted average interest rate on debt	2.20%			2.20%	1.80%
Term loan, amount outstanding	$ 500,000,000			$ 500,000,000	$ 346,200,000
Fair value of outstanding borrowings	450,500,000			450,500,000
Convertible Debt
Debt Instrument [Line Items]
Principal amount paid		227,100,000
Gain or loss on extinguishment		$ 0
Strike price of the call transaction (in dollars per share)									$ 26.42
Strike price of warrant transactions (in dollars per share)									$ 32.22
December 2016 Amendment
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity							$ 1,500,000,000.0
December 2016 Amendment | Term Loan
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity							500,000,000.0
December 2016 Amendment | Revolving Credit Facility
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity							1,000,000,000.0
December 2016 Amendment | Standby Letters of Credit
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity							60,000,000.0
December 2016 Amendment | Swingline Loan
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity							$ 60,000,000.0
August 2015 Amendment | Term Loan
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity								$ 350,000,000.0
August 2015 Amendment | Revolving Credit Facility
Debt Instrument [Line Items]
Senior credit facility, maximum borrowing capacity								$ 750,000,000.0
July 2014 Amendment
Debt Instrument [Line Items]
Cash balance threshold above which excess amount is not subject to any restriction of use or investment			$ 40,000,000
Capitalized incremental financing costs	4,500,000			4,500,000	1,400,000
Amortization of debt issuance costs				500,000
July 2014 Amendment | Minimum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage			0.15%
July 2014 Amendment | Maximum
Debt Instrument [Line Items]
Line of credit, commitment fee percentage			0.30%
July 2014 Amendment | Eurodollar
Debt Instrument [Line Items]
Interest rates available to the company at its option			1.00%
July 2014 Amendment | Eurodollar | Minimum
Debt Instrument [Line Items]
Interest rates available to the company at its option			1.00%
July 2014 Amendment | Eurodollar | Maximum
Debt Instrument [Line Items]
Interest rates available to the company at its option			1.75%
July 2014 Amendment | Federal Funds
Debt Instrument [Line Items]
Interest rates available to the company at its option			0.50%
Senior Credit Facility
Debt Instrument [Line Items]
Line of credit facility outstanding	$ 165,000,000			$ 165,000,000	$ 150,000,000
Weighted average interest rate on debt	2.20%			2.20%	1.90%
Available borrowings under senior secured revolving credit facility	$ 835,000,000			$ 835,000,000
Fair value of outstanding borrowings	147,700,000			147,700,000
Senior Credit Facility | Standby Letters of Credit
Debt Instrument [Line Items]
Line of credit facility outstanding	$ 500,000			500,000	$ 0
Amounts drawn				$ 0
2016 Convertible Senior Notes
Debt Instrument [Line Items]
Principal amount outstanding					227,100,000					$ 230,000,000
Interest rate on debt	1.625%			1.625%						1.625%
Carrying amount of liability					218,700,000
Unamortized discount					$ 8,400,000
Strike price of the call transaction (in dollars per share)	$ 28.72			$ 28.72
Strike price of warrant transactions (in dollars per share)	$ 35.03			$ 35.03